09042013 Ag Ab Interactions

7/28/2019 09042013 Ag Ab Interactions

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o immune-mediated hemolytic anemia.

o Hemolytic disease of the newborn

(ABO, Rh)

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o identify antibodies present in a

patient's serum prior before blood

transfusion.

o Blood transfusion preparation.

o Antenatal antibody screening.


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Aggregation ofparticulate antigens

bound with agglutinins of more than

one specificity.

Example: coagglutination

staphylococcus aureusprotein A for

serotyping strains of

Streptococc us pneumo niae,


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o Example: Influenza virus

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o Heterophiles antibodies tests (Monospot test, PaulBunnell test):o agglutination of the horse RBCs by heterophile antibodies in

patient's serum for rapid diagnosis of EBV infectiousmononucleosis.

o Cold agglutnin test:o Cold agglutinins are antibodies made by the immune system in

response to infection having the ability to agglutinate RBC in Lowtemperature. E.g. Mycoplasma pneumoniae

o Weil felix test:o it is agglutination test for the diagnosis ofrickettsialinfections.

o based on the presence of antigenic cross-reactionbetween Rickettsia and certain serotypes of Proteus

o VDRL: screening for syphilis caused by treponema

pallidum.

o Widal test: standard tube agglutination test forsalmonella typhi.

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oIt is a reaction in which the Abinteract with a free soluble Ag .

oAt the optimum concentration

,positive reaction form a precipitin

line


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oThis is precipitation reaction to

test identity between two antigens

or between two antibodies


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test identity between two antigens

or between two antibodies


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Ag

Mg/ml

Diameter /mm

Sample

Diameter

Sample

concentration


test presence of entire subclass of

immunoglobulin by applying

specific antiglobulin forming a

precipitation rings.


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oThis is method to separate the serum by electrophoresis.

oCreate a trench containing specific anti serum.

oDiffusion of both serum and anti serum forming a precipitin lines


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o technique used to detectspecific proteins in the givensample.

o It uses gelelectrophoresis to separateproteins (or polypeptide) andare then transferred to amembrane.

o (nitrocellulose) where they

are stained with labledantibodies specific to thetarget protein.


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SampleABTest Ag Enzym linked Ab Enzyme substrate


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oAntibodies containing fluorescent dye react with serum

(either Ag or Specific Ab)..

oPositive reaction is shown under fluorescent microscope.


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The toxin( hemolysin) sample (serum) Ab RBC lysed with the toxin

oTesting the presence of the

antitoxin in the serum.

oIf they are present the toxin

will be neutralized .RBCs not

lysed.

oIf there is no antitoxin the

toxin will lyse the RBCs


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The toxin( hemolysin) sample (serum) Ab RBC lysed with the toxin


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o Testing immunity of the patient against diphtheria.

o 0.2 ml of the diphtheria toxin in the test forearm and 0.2 ml of

inactivated diphtheria toxin (by heat ) in the control forearm.


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oPreparing sensitized complement & two

systems:

oSystem1:oContaing serum sample & prepared

antigen

oSystem 2 (indicator system):

ocontaining sensitized sheep RBCs

& Ab to sheep RBCs.

oIn +ve reaction the serum containing Abwill react with the Ag the complement will

be consumed by system 1 (RBCs will not

be lysed)..

oIn ve reaction where there is no Ab in

the serum so the complement will

consumed by system 2 (RBCs will belysed).Tes t Ag Sam ple A B com plem ent Sheep RB C A b t o sheep RB C


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Sample ABTest Ag complement Ab to sheep RBCSheep RBC


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oThis a solid phase reaction through

which the serum antibody will be

captured to the wells using capture

Ag.

oAn Antihuman globulin conjugate

containing chromogenic enzyme will

react with the sample Ab.

oAdding enzyme substrate will

produce colour on the well.

oSo +ve test is manifested by

presenece of colour , in ve testthere is no colour.
http://localhost/var/www/apps/conversion/tmp/scratch_9/ELISA.mov


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Sample ABAg Enzym linked Ab Enzyme substrate


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which the serum antibody will be


Ag.

oThe conjugate here is directed to the

Ag i.e. the sample and conjugate will

compete each other.

oAdding enzyme substrate will not


oSo +ve reaction is manifested by no

colour , -ve reaction there is a colour.


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Sample ABAg Enzym linked Ab Enzyme substrate


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which the serum antigen will be


Ab.

oThe conjugate here is directed to the

Ag i.e. the Ag will be sandwiched

between capture & test Abs

oAdding enzyme substrate will


oSo +ve test is manifested by

presenece of colour , in ve test thereis no colour.


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ABSampleAg Enzym linked Ab Enzyme substrate


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o is a biophysical laser basedtechnology employed in cellcounting, cell marker detection,allowing synchronized analysis ofthe physical

and chemical characteristics of upto thousands of particles persecond.

o

Example: used in thediagnosis blood cancers, and CD4cell counting in AIDS patients

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o rapid and easy.o Antigen-antibody immune

complexes flow through a

region and encounter

antibody against them,

resulting in a visible coloured

line

o E.g Used in rapid diagnosis of

Malaria

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http://localhost/var/www/apps/conversion/MICRO%202007/PROTOZOA/ICTF.exe

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09042013 Ag Ab Interactions